The NAVSTAR 63 (GPS 2R-20) spacecraft will rejuvenate one of the navigation constellation's positions, while also conducting critical tests of a new signal to be fielded by follow-on satellites. The craft will replace the aging GPS 2A-27 satellite launched in September 1996. Now well past its design life, ground controllers plan to move the old satellite into a backup role. The new GPS 2R-20 spacecraft will take over the Plane B, Slot 2 location of the navigation network, considered one of the primary positions in the constellation that is divided into six orbital groupings with multiple satellites flying in each.